Compact coiled tube heat exchanger



Feb. 28, 1967 J, RR N 3,305,352

COMPACT COILED TUBE HEAT EXCHANGER Filed Feb. 10. 1965 INVENTOR. John Leo Curran United States Patent Office 3,306,352 COMPACT COILED TUBE HEAT EXCHANGER John Leo Curren, 765 W. th St., Wilmington, Del. 19806 Filed Feb. 10, 1965, Ser. No. 431,536 4 Claims. (or. 165-163) steam heating boilers or hot water heating boilers. Yet

another object of this invention is its use as a supplemental unit, where and when intermittent peak demands for high temperature hot water cannot be supplied by the regular installed domestic hot-water system.

These objects are accomplished by a heat exchanger consisting primarily of (a) a housing made of a section of heavy weight streamline tubing or piping, with prebulged heads attached in each end, said housing having an inlet and outlet as noted below; (b) a pipe assembly extending through each of the mentioned prebulged heads; (c) a series of coils vertically disposed in the housing and attached to the pipe assembly; and (d) a spiral wiping vane spaced in the center of each coil.

The heat exchanger of this invention in its preferred embodiment is described more specifically with reference to the accompanying drawings wherein:

FIG. 1 is a sectional plan taken substantially on the line BB of FIG. 2.

FIG. 2 is a sectional elevation taken through the center of FIG. 1.

Referring to the drawings, in which like reference characters indicate like parts, this new heat exchanger has component parts as herein noted.

A housing or jacket 1, preferably of copper, having prebulged ends or heads 2, and an inlet 6, and an outlet 5 for introducing and withdrawing liquid heat exchange medium (normally the heat absorbent). The ends 2 are provided with an opening preferably at or near the center, to provide clearance for top and bottom sections of a novel pipe assembly, described below, for introducing the other heat exchange medium (normally the heat supplier, particularly steam).

A pipe assembly 3 which is vertically disposed in jacket 1, and extends through and beyond the ends thereof, as shown in FIG. 2, to form a pressure tight vessel with above mentioned inlet 6 and outlet 5. This pipe assembly, which is preferably of brass, comprises an upper section 12, and a lowersection 13. The upper and lower sections of the pipe assembly are separated and connected through reducers 14, as shown in FIG. 2, to a smaller section of pipe 15. Pipe plug 16 is inserted in upper end of smaller pipe to complete formation of the steam supply or pressurized chamber 12, and the return or condensate non-pressurized chamber 13. The top and bottom sections of the said pipe assembly, are provided with a notched groove 9, said grooves objectively placed within the weld areas at each end of exchanger, and func tions to further aid retention of internal pressure.

A nest of objectively sized tubular coils 4, preferably of copper, vertically positioned within the jacket 1. These coils are, advantageously circularly disposed around pipe assembly 3, as shown in FIG. 1. The upper end 10 of each coil is connected to the supply chamber 12, and

3,306,352 Patented Feb. 28, 1967 the lower end 11 of each coil is connected to the return chamber 13 of the pipe assembly.

A close fitting spiral wiping vane 8 is positioned in the center of each coil 4 and preferably extends the full length of the coil.

Refinements in the construction of this heat exchanger include the following additional features. Lock and flared joints 7 are provided on the exchanger ends of inlet 6 and outlet 5 to serve as a positive arrestor against dislodgement by internal pressure.

When this exchanger is put into operation, the housing is always full of water, or other liquid medium, before admission of steam to steam chamber for distribution to each of the vertical coils. Study has proven that, in vertical liquid flow, the steam flow must be countercurrent for high efiiciencies.

The materials of construction can be greatly varied, as can the length, diameter, number and size of coils, so that capacities can be predetermined. In design of this exchanger, allowances are made for absorption of most heat in the condensate near bottom of coil. This phase of heat absorption allows for pressure-free condensate at point of discharge, thereby eliminating use of any thermal or pressure-actuated steam trap. Similarly, the outside diameter of the housing section is so chosen for a minimum clearance around the nested vertical coils, which extend from the steam changer to the condensate chamber.

The above-mentioned piping assembly has a four-fold function, as follows: (1) It furnishes a degree of rigidity in the vertical plane, (2) the enlarged top section of this assembly functions as a steam distribution chamber, supplying steam to each of the nested vertical coils, (3) the bottom enlarged section of this assembly functions as a condensate chamber, made free of pressure by insertion of /2" brass pipe plug in top of A" schedule section of brass pipe as shown in FIG. 2, (4) the top and bottom sections of this assembly are provided with a notched groove, said groove functioning as a key joint to further internal pressure retention.

The heat-exchanger in this invention has the following features and advantages: (a) designed for simplicity of manufacture, (b) designed for highest B.t.u. capaci ties per unit weight, (c) easily portable for certain remote uses, (d) in assembly, cold spring is app-lied to each coil, in its vertical plane, for the purpose of elimination of stresses or strains, due to variables of heat application to the coils, (e) designed to furnish an unlimited supply of high temperature water, which temperature is strictly prohibitive for any regular industrial or domestic hot-water system, (f) designed for batch load heating up to 210 F., (g) designed for use, with proper valving, for open flow service at any constant volume, and constant temperature up to 210 R, such as required in dairy, food processing, candy and drug manufacture, and in other types of industry, (h) designed to function economically as a preheater.

Insofar as I am aware, no other heat-exchanger has these advantages, at least not to an equal degree. The design of this invention is totally novel in itself, and embodies engineering features not apparent in any other heat-exchanger, at least not to my knowledge.

Although the heat-exchanger in this invention has been described as a water heat-exchanger, with particular reference to water and steam as the media of use, it is apparent that other media can be used. Also in this reference it is apparent that a substitution of metals could be applied, where advisable. In such applications, the design and assembly as shown in the drawings do apply. This invention has been described in its more simple form. It is within the scope of this invention to include all refinements, internal and external of the exchanger proper, which are part and parcel of any phase of this heat-exchanger, including the field of all domestic or industrial uses.

Having now described the invention in specific detail, and exemplified the manner in which it may be carried into practice, it will be readily apparent to those skilled in the art that innumerable variations, modifications, applications, and extensions of the basic principles involved may be made without departing from its spirit and scope.

What is claimed is:

1. A heat exchanger comprising:

(a) A jacket having bulged top and bottom sections, and having an inlet and outlet to permit passage of a liquid through the jacket,

(b) A pipe assembly vertically disposed in said jacket, and extending through the top and bottom thereof, said assembly having an upper supp-1y chamber hermetically sealed from a lower return chamber,

(c) A nest of tubular coils vertically disposed in said jacket and positioned in close proximity to the jacket and the pipe assembly, the upper end of each coil being connected to the supply chamber of said pipe assembly, and the lower end of each coil to the return chamber of said pipe assembly, the combined cross sectional areas of the tubes comprising said coils being less than the cross sectional area of the supply chamber, and

(d) A thin spiral wiping vane in the center of each coil.

2. The heat exchanger of claim 1, wherein the top and bottom sections of the pipe assembly each contain a notched groove at the locus where the pipe assembly extends through the jacket thereby forming key joints to aid retention of internal pressure.

3. The heat exchanger of claim 1, wherein the upper and lower chambers of the pipe assembly are hermetically sealed from each other by means of a smaller diameter section of pipe which is connected to said upper and lower chambers through reducers and which has a pipe plug inserted in its upper end.

4. The heat exchanger of claim 1, wherein the internal ends of the inlet and outlet of the jacket have lock and flared joints to serve as a positive arrestor against dislodgement by internal pressure.

References Cited by the Examiner UNITED STATES PATENTS 281,014 7/1883 Butman 165-l63 361,803 4/1887 Andrews 165--163 1,278,311 9/1918 Davis 165163 1,438,596 12/1922 Harding 165177 X 1,893,484 l/1933 Belt 165163 X 1,991,980 2/1935 Hetzer 165-463 X 2,602,644 7/1952 Sandstrom l65163 X FOREIGN PATENTS 5,918 1900' Great Britain.

ROBERT A. OLEARY, Primary Examiner.

A. DAVIS, Assistant Examiner. 

1. A HEAT EXCHANGER COMPRISING: (A) A JACKET HAVING BULGED TOP AND BOTTOM SECTIONS, AND HAVING AN INLET AND OUTLET TO PERMIT PASSAGE OF A LIQUID THROUGH THE JACKET, (B) A PIPE ASSEMBLY VERTICALLY DISPOSED IN SAID JACKET, AND EXTENDING THROUGH THE TOP AND BOTTOM THEREOF, SAID ASSEMBLY HAVING AN UPPER SUPPLY CHAMBER HERMETICALLY SEALED FROM A LOWER RETURN CHAMBER, (C) A NEST OF TUBULAR COILS VERTICALLY DISPOSED IN SAID JACKET AND POSITIONED IN CLOSE PROXIMITY TO THE JACKET AND THE PIPE ASSEMBLY, THE UPPER END OF EACH COIL BEING CONNECTED TO THE SUPPLY CHAMBER OF SAID PIPE ASSEMBLY, AND THE LOWER END OF EACH COIL TO THE RETURN CHAMBER OF SAID PIPE ASSEMBLY, THE COMBINED CROSS SECTIONAL AREAS OF THE TUBES COMPRISING SAID 